1. Field of the Invention
The present invention pertains to water treatment and water purification. More specifically, the present invention pertains to apparatus for filtering and/or ultraviolet treatment of water flowing from a water supply.
2. Description of the Prior Art
Most sources of water are contaminated to varying degrees. In an attempt to remove some of these contaminants, various methods and apparatus have been developed over time. Small suspended particles in water may be removed by mechanical filtration. Other types of filters, such as activated carbon may be utilized to remove other impurities which affect taste, odor, color, chemical composition, etc. Ultraviolet light (U.V.) has been used to destroy viruses and bacteria in water.
In commercial applications, where water is filtered and treated with U.V. rays, filtration and U.V. purification are performed in separate apparatus. After filtering, the water may flow through a stainless steel chamber in which an ultraviolet lamp has been inserted. The water flows into the chamber, around the U.V. lamp and out of the chamber. The stainless steel chamber is typically cylindrical and its inner surface is polished to reflect U.V. rays from the U.V. lamp to enhance or increase the effectiveness thereof. Such stainless steel chambers are relatively expensive.
In recent years, combination water filters and sterilizers have been developed which utilize mechanical and carbon filtering in combination with ultraviolet sterilization of water in a composite unit. Such units, developed primarily for household uses, may be connected to a residential water tap and supplied with power for an ultraviolet lamp by ordinary 120 volt A.C. current. Examples of such combination water filter and sterilizers may be seen in U.S. Pat. Nos. 3,551,091 and 4,971,687.
In such combination water filter and sterilizers, a typical off-the-shelf annular filter surrounds a quartz tube into which is inserted an elongated ultraviolet lamp. The outer surface of the quartz tube and the inner surface of the annular filter define an annular passageway through which water passes, after filtration by the filter means, for exposure to ultraviolet rays emanating from the ultraviolet lamp. In U.S. Pat. No. 4,971,687 an elongated teflon or other transparent material tube is provided between the annular filter and the quartz tube surrounding the ultraviolet lamp to assure maximum time of exposure of the water to ultraviolet rays before exiting the unit. While such an arrangement may enhance ultraviolet light sterilization of the water, it also complicates the manufacturing of such a unit and increases the cost thereof. Other off-the-shelf filters are provided with inner and outer liners, between which filter materials are disposed, which direct the flow of water from one end of the filter to the other prior to exposure to U.V. treatment.
One of the major problems associated with combination and filter and sterilization units such as those just described is in sealing around the tube which surrounds the ultraviolet lamp. The tube must of necessity be opened at one end so that the ultra-violent lamp may be inserted thereinto. The open end must then be sealed, usually in a head or base unit to which it is attached, so that no water leaks past this connection for possible exposure to electrical components which provide power for the ultraviolet lamp. Most units of the prior art provide an O-ring seal around the open end of the hollow tube which frequently does not satisfactorily seal against household water pressure which may exceed 90 psi.
Thus, while a number of fairly satisfactory combination filter and sterilization units have been developed, the search continues for such units which are safe, efficient, cheap, easy to maintain and of improved ability to filter and purify water.